JPS5829318A - Digital protecting relay system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a digital power protection device and a digital protection relay system for protecting a power system using a digital computer in the relay.

In recent years, protective relay devices using digital calculations have been developed, and there is an opportunity for their practical use.

FIG. 1 shows a general configuration example of a digital electronic device. Oh! In I, la and lb are input converters into which each phase voltage and each phase current of the power system to be protected are introduced, and the input electrical quantity is converted into a voltage signal of an appropriate magnitude.

2CL, 2b are filters, and input converter 1a
, removes harmonic components contained in the output of lb. s
Each filter 2a is a butterfly pull-hold circuit.

The output from 2b is sampled at predetermined intervals.

4 is a conversion circuit for sample/hold circuit FJI.
The output from Ig is added via multiplexer tSt,
Convert this into digital data. 6 companies direct
Memory access (CDMA) 1 circuit, N conversion circuits 40 inputs l are added. 1 is a memory circuit and DM
The output of the conversion circuit 4 is written to a predetermined address by A1i. 8 is read O only memory (ROM)
It has a built-in program. Reference numeral 9 denotes a central processing unit (CPU) which executes relay calculations according to a program written in the ROM 8 using the voltage and current data of the 9 electric power system written in the memory circuit IK. W is an output circuit which outputs a plow cutter side tilt command based on the calculation results of the CPU 90.

Next, the operation of the digital relay having the above configuration will be explained with reference to the flowchart shown in the second figure.
The calculation of B-5) will be explained as an example. Now, the voltage and current data from the power system are input to converter 1alb, filter 2m,
2b, sample and hold circuit 3, multiplexer S%
It is assumed that the signal is input to the DM memory via the A/Df conversion circuit 4 and is written to a predetermined address in the memory circuit 70. In this state, when the CP09Kll calculation start command is input, the CPU performs the following calculation using the voltage and current data written in the memory circuit 7 according to the program written in the ROM8K. Perform calculations.

That is, when the calculation is started in step 21 in the second @, the next value is calculated from the predetermined voltage/current data in step n.

a = V @ l5it # -1・-(11
However, V and I are the input voltage and the amplitude value of the current, - is the angle step field formed by the voltage and current, and the following equation is calculated.

b−■*, −−−−−−−+21 steps, the system flux actance is calculated using the following formula.

X-ψ ---131 The stepper compares the calculated actance X with the set value Zx. As a result, in the case of
) ) '/d, non-11h crop judgment sale, X<Zl
In the case of c, the reactance element is determined to be in operation at step γ, and the process ends with step recommendation. The software of the digital relay executes not only the above-described good relay function but also a sequence control function. Figure 3 shows nine examples of this. In FIG. 3, (448-8U) shown in step 31 is a direction element that indicates whether the accident is ahead or behind when a system accident occurs;
018-0) shown in step 32 is a distance measuring element that measures the distance to the fault point and determines whether the fault point is within the protected area. This is an undervoltage element that indicates that the The AND gate shown in step 34 is
On the condition that all elements of 1 are in operation, a trip command is issued through the output circuit 10t shown in the figure. Figures 4(a) and 4(b) show the characteristics of each of the relay elements.

Figure 5 shows how the functions shown in Figure 3 can be implemented using software. The brooch is shown when executed.

That is, in step 5tFi, (zy8)O operation determination section, when the operation is determined, the operation is performed as shown in step s2 (44S-
8U) Move to the operation determination section. and step 52 (4
48-8U) If it is a crab motion, it is shown in step 53 (
The process moves to the operation determination section of as8()). Said in the trap (448
-0) is in operation, a trip command is issued in step 54.

If any of steps 51 to 53 is inactive, the process branches to step 55 to determine if it is inactive and does not issue a trip command.

As is clear from the above example, one percent of the digital relay
The statue is 1. Its main function is realized by software. Furthermore, since the functions are realized by software, there are the following advantages.

1) Standardization of software is easy because completely different functions are performed by the same software.

11) Complex functions that conventionally could not be realized with hardware can be easily realized with software.

111) Functions can be changed more easily than hardware changes.

However, regarding 11) above, special attention must be paid to butterflies.

That is, if the equivalent function is implemented by software, the configuration will be large-scale, but this advantage is realized if it is easily implemented by software.

However, on the other hand, it must be kept in mind that while hardware can easily change functions, software can require relatively more effort.

For example, in the sequence function shown in Figure 3, (278
) is replaced with an overcurrent relay element (51f9) K (see Figure 6).

Assuming that the (sis) determination function is originally provided, the change from Figure 3 to Figure 6 is configured by hardware, and the companion device only needs to change one or two wires. , can be carried out very easily and reliably. However, when this is written to IC 6 and executed by mourning software, the program is changed in the form of writing to the ROM, so in reality, not only the changed part of the program but also the part where other functions have not been changed. must be rewritten at the same time. Furthermore, it is necessary to confirm that the changed part does not affect other programs, and even simple program changes require an unexpected amount of testing time.

The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a digital protection relay system that allows software functions to be changed without changing the program.

Examples will be described below with reference to the drawings. The off-line diagram is a block diagram of an embodiment according to the present invention, FIG. 8 is a flowchart for implementing the present invention, FIG. 9 is one of the software functions changed by FIG. 8, and FIG. Fig. 11 (&) shows a flowchart for realizing the sequence function, and Fig. 11 (&) shows another different sequence function.
Figure 1 is a flowchart for realizing the jitance function, and Figure 1 is a flowchart for realizing another sequence function.

In the off-diagram, symbols 1a to io#i correspond to FIG. Reference numeral 11 denotes a control signal input circuit which internally includes an operating section 11a such as a digital switch and an input register ub, and inputs a control signal to the CPU 9 through the input register llb by operating the digital switch Ha from the outside. This controls the program's arithmetic routines and changes the functionality of the software.

Although various types of control signal input circuits are conceivable, in this embodiment, for example, a digital switch is used, and the functions of the software are changed by control signals consisting of specific numerical values.

As specific numerical values, for example, when the control signal is "1", the undervoltage element I is designated, and when the control signal is "2", the overcurrent relay element 518 is designated.

The operation will be explained with reference to the illustrated flowchart. In FIG. 8, 448-8U in step 85 is a direction element;
Similarly, 448-0 in step 82 is a distance measuring element, 278 tf undervoltage element in step 84, and 51 in step 86.
8 is overcurrent relay a1! There are nine ways to be elemental. Therefore, in this flowchart, the calculation routine is changed by switching between the software function including the undervoltage element 278 and the no-ware function including the overcurrent relay element 518 in response to an external control signal. It is.

That is, in step 81 the direction element port 5-ISU.

After confirming the operation, in the next step 82 the ranging element 44
The process is the same as the conventional method until the operation of 8-0 is confirmed. Step 83 reads the control signal from the control signal input circuit 11 shown in FIG.
['Perform elemental determination. If the control signal is not rlJ in step 73, the process proceeds to step Is, where it is newly determined whether the control signal is "2". And “2”
If so (designation of overcurrent relay element sis), the process advances to step 86, and 618! ! Performs an elementary motion judgment. The control signal from the control signal input circuit 11 is "1" or "2".
”, the program proceeds to step 88 and determines that the device output is inactive. However, if it is determined in step U or 86 that there is an operation, the process proceeds to step 88, where the operation is determined as the device output and a trip output is derived.

It goes without saying that by setting the control signal 'frrlJ to a value other than 2, a function that does not require 27S or 518 can be realized.

Figure 0 (false) and 11th WAh> are both other trip sequences, and Figure 1G (a) is the direction element 44S.
-8U.

Undervoltage element for distance measuring element 448-OK? 7S and overcurrent relay elements! +18 AND condition is added. And the 100th Cathedral) is the ninth 70th that realizes that function.
-It is a chart.

In FIG. 11 (sl), the OR condition of the undervoltage element 27B and the overcurrent relay element 518 is added to the direction element 44g-8U and the distance measuring element 448-0. FIG. 11(b) is a flowchart for realizing the function.

FIG. 4 is a flowchart for realizing yet another sequence function, which has been modified so that any of the functions 1a in FIGS. 10 and 11 can be utilized by control signals from the control signal input circuit. Step 12 in Figure 4
1 is a direction determining element, step 122m11 is a distance element, step 118 ii is a control signal determining element, steps 124 and 12d are undervoltage elements, step 1! ! 6 and 126
is the overcurrent relay element. and steps 124 and 1
26 by undervoltage element 278 and overcurrent relay 51B
Configure the case in ND4 with the same steps 125 and 1.
27 by undervoltage element 278 and overcurrent relay element 5
This constitutes an OR condition with 18.

Therefore, if the control signal is "1" in step 123, the undervoltage element is designated and the process proceeds to step 124, but if the undervoltage element 278 is inoperable in step 124, the overcurrent relay is activated in step 126. Since the ANDe condition with element 51B does not hold, it is determined that the device output is inactive.

On the other hand, if the control signal is not rlJ in step 123, the process proceeds to step 125, and the OR condition is satisfied if the undervoltage element 21B operates, or if 278 does not operate and the overcurrent relay element 51B operates in step 127. Then, the device output will be used to judge the operation. The other operations are the same as those described above, so a detailed explanation will be omitted. In this way, the operation that satisfies both the functions shown in FIGS. 10 and 11 is performed.

Note that in the above description, the operation section 11 of the control signal input circuit
Although a is a case of a digital Q switch, it is not limited to the above configuration, and any other method can be used as long as the control signal can be identified in the calculation unit, such as a snap switch to output an on/off signal. It goes without saying that this method is also applicable, or even a method in which control inputs are changed by changing the connections using jumper wires.

As explained above, according to the present invention, a control signal input circuit is provided in the calculation section, and the calculation routine of the program is controlled by external control signals, and the bridge function of the software is changed. It is possible to effectively deal with changes in the functions of the digital protective relay device.

[Brief explanation of the drawing]

Figure 5 is a general configuration diagram of the digital protection and relay power type.
The figure shows a 70-chart when calculating reactance elements using a digital protective relay, Figure 3 is a configuration diagram of a short-circuit protection sequence, Figure 4 is a characteristic diagram of relay elements in the event of a short circuit, and Figure 5 shows a short-circuit protection sequence. A flowchart of a program to realize the program, FIG. 6 is an example in which an undervoltage element is replaced with an overcurrent relay element in a short circuit protection sequence, an OFF diagram is a block diagram of an embodiment according to the present invention, and FIG. 8 is an example of implementing the present invention. 70 one chart for 9th figure is 8th
One of the software functions modified by the diagram, number 10
Figure (a) shows another different sequence function, the 10th
0) is a flowchart for realizing the sequence function, FIG. 11(&) further shows another different sequence function, FIG. The figure is a flowchart for realizing yet another sequence function. 1B, lb...Input converter, 2m, 2b...Filter, 3...Sample/hold circuit, 4-...L[
F] conversion circuit, 5... multiplexer, 6...
Direct memory access device, 7... memory circuit,
8.-Read-only memory circuit, 9.--Central processing unit, '1G-output circuit, 11.. Control signal input circuit, Patent applicant Tokyo Shibaura Electric Co., Ltd. Agent Patent attorney Nori Ishii Oma 2 Figure 3 Horse 9 Figure 10 (α) Figure 11 (α)

Claims (1)

[Claims] A number circuit that samples either a voltage signal and a current from an electric power system or a voltage signal or a current signal at predetermined time intervals; and an analog-to-digital conversion circuit that converts the sampled data into a digital quantity. , a memo 9B path for storing digital data that has been converted into a digital quantity, a memory circuit containing a rounding program for arithmetic processing, an arithmetic unit that performs predetermined arithmetic operations using the digital data, and an external The digital control system is equipped with a control signal input circuit for inputting a control signal, and changes software functions by controlling a boogram calculation routine according to an external Q control signal.